1. Field of the Invention
The present invention relates to an apparatus and method for converting color data using a color gamut extension, and more particularly, to mapping input colors and converting color data as to the mapped colors to CMYK data by use of a CMYK color gamut that is extended from a CMY color gamut.
2. Description of the Related Art
Most of printers commercially available on the market use four colorants of a cyan (C) colorant, a magenta (M) colorant, a yellow (Y) colorant, and a black (K) colorant. The addition of the K colorant provides for color gamut extension and increased cost effectiveness.
Thus, an apparatus is required to convert color data of the input colors, such as RGB data, to CMYK data.
FIG. 1 is a block diagram of, a conventional apparatus for converting RGB data to CMYK data. As shown in FIG. 1, the apparatus includes a color mapper 10, a color data converter 20, and a K substitution part 30.
The color mapper 10 converts input colors, as RGB data, to CIE L*a*b color space data in a CMY color gamut. The color data converter 20 converts the color data CIE L*a*b, which is mapped at the color mapper 10, to CMY data. The K substitution part 30 converts the CMY data that is output from the color data converter 20, to the CMYK data. As a result, the CMYK data is output from the K substitution part 30.
The final color data output from the apparatus for converting the color data is CMYK data, but the CMY color gamut is used for the color mapping at the color mapper 10. As the K substitution part 30 converts the CMY data to the CMYK data, the ratio of the C, M, and Y colorants for the input color is decreased while the K colorant is added at a proper ratio. Thus, the CMY data can be converted to the CMYK data.
However, the above conventional color mapping and color substitution causes unnatural color reproduction and printing with respect to low-lightness colors and high-saturation colors.